The present invention relates to an illuminating and optical apparatus for inspecting soldering of a printed circuit board, and more particularly, to the illuminating and optical apparatus which uniformly illuminates and photographs a variety of electronic parts mounted and soldered on the printed circuit board of a surface mounting apparatus to automatically inspect the mounted and soldered states thereof.
In general, a surface mounting apparatus is used for automatically fixing a variety of electronic parts, such as an integration element, a resistor, a condenser, and the like by directly soldering the electronic parts on the printed circuit board (hereinafter referred to as PCB). That is, without separate soldering lead wires to fix on the PCB, those electronic parts have electrodes for directly soldering the electrodes. In this way, there will be advantages such as reducing the size of electronic parts, substantially improving assembling and manufacturing speed because a separate hole does not have to be formed for fixing electronic parts on the PCB, and decreasing the size of a product.
In soldering various parts with the surface mounting apparatus, the parts are so small that they can not be accurately mounted on the PCB or the amount of solder is so great that the potential may be high for two adjacent electrodes bringing about a lot of errors, such as a short circuit and the like. Therefore, after finishing up soldering parts, mounted and soldered states thereof are inspected to decrease a defective rate of products.
In order to inspect the mounted and soldered states of the parts soldered at the surface mounting apparatus, a number of workers are needed for manual inspection, but it is hard to achieve uniformity of the manual inspection.
Therefore, in case of inspecting the mounted and soldered state of the part soldered on the PCB, an automatic inspection process has been performed by illuminating, and photographing the inspecting parts with a camera and screening the mounted and soldered states of the parts with resultant photographs.
FIG. 1 is a schematic view illustrating an embodiment of a structure and an operational state of a conventional illuminating and optical apparatus which illuminates and photographs mounted and soldered states of an electronic part on a PCB for automatic inspection.
At this time, reference numeral 10 denotes the PCB. Reference numeral 11 denotes an electronic part such as integration element, resistor and condenser and the like of which mounted and soldered states on the printed circuit board are inspected. Also, reference numeral 12 denotes a disturbing part adjacently positioned to the inspecting part soldered on the PCB, which interferes with the proceeding route of the light in inspecting the mounted and soldered states of the part on the PCB.
Reference numerals 13, 14, and 15 respectively denote upper, middle and lower light emitting parts, all of which illuminate the inspecting part 11. All of those light emitting parts are made up of a plurality of lamps arranged in a ring shaped fixtures of different diameters and different heights therebetween.
Symbols H1, H2, and H3, respectively, denote a height of the upper, middle, and lower light emitting parts 13, 14, 15 arranged at different heights having the relationship of H1 greater than H2 greater than H3. On the other hand, symbols D1, D2, and D3, respectively, denote a diameter of the upper, middle, and lower light emitting parts 13, 14, 15 arranged at different diameters having the relationship of D1 less than D2 less than D3.
All of those light emitting parts 13, 14, 15 are fixed with an identical center axis.
At this time, for instance, light emitting diodes are used for a plurality of lamps.
Reference numerals 16, 17, respectively, denote a camera and lenses positioned over the center axis of all the upper, middle, and lower emitting parts 13, 14, 15 for photographing the inspecting part 11 while being illuminated by the upper, middle, and lower light emitting parts 13, 14, 15.
For example, the camera 16 takes a photograph of the inspecting part 11 with a charged coupled device CCD.
When the conventional illuminating and optical apparatus thus constructed is used for inspecting the mounted and soldered states of the part 11 on the PCB 10, all the lamps of the upper, middle, and lower light emitting parts 13, 14, 15 are turned on to illuminate the inspecting part 11.
At this state, the camera 16 takes an image of the inspecting part 11 illuminated by the upper, middle, and lower light emitting parts 13, 14, 15 through the lenses 17. The photographed image of the inspecting part 10 is inputted and further processed by an inspection apparatus, such as an inspection computer system or the like to inspect the mounted and soldered states of the part 11 on the PCB 10.
However, in the conventional illuminating and optical apparatus, the incident light of the upper, middle, and lower light emitting parts 13, 14, 15 is focused only on a position of the inspecting part 11, that is, at a center of a photographing view of the camera 16. As a result, the center of the photographed image is brightest. On the other hand, the closer a position gets to the edge of the image, the image becomes darker.
Therefore, as an image processing condition should be differently set up depending on positions of the same image of an identical inspecting part 11, it is difficult to make a standard inspection condition.
FIG. 2 is a schematic view illustrating another embodiment of a structure and an operational state of a conventional illuminating and optical apparatus. As shown in FIG. 2, the illuminating and optical apparatus includes light diffusers 13a, 14a, 15a below the upper, middle, and lower light emitting parts 13, 14, 15.
In this case, light illuminated by the upper, middle, and lower light emitting parts 13, 14, 15 are diffused by the light diffusers 13a, 14a, 15a, thereby relatively evenly illuminating the inspecting part 11.
However, as the illuminating light is diffused, the amount of light actually directed on the inspecting part 11 has substantially decreased. Therefore, it is difficult to adequately illuminate the inspecting part 11 for inspection. In addition, because the diffusion degree of light varies in response to the quality of a material of the diffuser, it is difficult to evenly illuminate the inspecting part 11 for inspection up to the required level.
Besides the aforementioned problems, there are further problems, which will be de scribed below, in the conventional apparatuses for accurately inspecting the mounted and soldered states of the inspecting part 11.
First, as only the upper, middle, and lower light emitting parts 13, 14, 15 are used for illuminating and photographing the inspecting part 11, it has been difficult to distinguish a soldering portion of the inspecting part 11 from a pattern of the PCB 10 or the body of the inspecting part 11, or the electrode of the inspecting part 11 from the body of the inspecting part 11 or the soldering portion. Therefore, it is difficult to simultaneously inspect both, the mounted and soldered states of the inspecting part
Second, if the disturbing matter 12 positioned around the inspecting part 11 is larger than the inspecting part 11 itself, the light emitted by the lower light emitting part 15 tends to be interfered with or blocked by the disturbing matter 12, causing a light interference phenomenon. Therefore, the required illumination effect can not be obtained, thereby reducing reliability of the inspection process.
Third, there is no control means available for controlling the brightness of the upper, middle, and lower light emitting parts 13, 14, 15, thereby causing inconveniences when in use.
Fourth, a single size of the camera view is available for grasping the inspecting state. In other words, only the camera 16 is utilized at an identical magnitude for photographing the inspecting part 11. Therefore, it is impossible to adequately correspond to different sizes of the inspecting part 11, thereby reducing the inspecting speed.
It is an object of the present invention to provide an illuminating and optical apparatus for inspecting soldering of an inspecting part on PCB, including light emitting parts to evenly illuminate the inspecting part; and a camera set comprising different view magnitudes to photograph different view sizes of images in accordance with the sizes of the inspecting part to inspect the mounted and soldered states of the inspecting part.
In order to accomplish the aforementioned object, an illuminating and optical apparatus for inspecting soldering of a PCB, including: a fixed member comprising a horizontal plane at an upper plane thereof and a tilted plane at the side thereof; first illuminating means disposed at the upper plane of the fixed member for illuminating an inspecting part attached to the PCB; second illuminating means disposed at the tilted plane of the fixed member for illuminating the inspecting part to obtain an image having a shade inverted to that obtained by the first illuminating means; control means for controlling a brightness of the first and second illuminating means and turning power thereof on/off; and optical means disposed at the upper plane of the fixed member for photographing large and small views of the inspecting part illuminated by the first and second illuminating means under the control of the control means.
A photograph hole formed on the fixed member, wherein the first illuminating means comprises lamps arranged in ring-shaped fixtures of different diameters therebetween and having identical heights thereto, and the lamps are installed adjacent to the photograph hole of the optical means formed on the fixed member. The second illuminating means comprises lamps arranged in ring-shaped fixtures of different diameters and heights therebetween. The lamps arranged in ring-shaped fixtures located at a lowest end of the second illuminating means are disposed adjacent to a lower portion of the tilted plane of the fixed member. Lamps are arranged in ring-shaped fixtures located at an uppermost portion of the second illuminating means and located at a predetermined angle between a straight line formed by the ring-shaped fixtures arranged at an outermost portion of the first illuminating means connecting a center of the inspecting part positioned at a predetermined height and another straight line formed by the ring-shaped fixtures arranged at the uppermost portion of the second illuminating means connecting the center of the inspecting part positioned at the predetermined height.
Furthermore, the control means includes a power switch; a light control unit varying a resistance value by controlling a plurality of light switches; and an output unit outputting electric current in accordance with the resistance value of the light control unit when the power switch is turned on and applying the electric current to the first and second illuminating means.
The optical means includes reflected light transmitting means for transmitting a half of the light reflected by the inspecting part; large and small view cameras which respectively photograph the half of the light reflected by the inspecting part; and large and small view lenses respectively assembled in front of the large and small view cameras controlling view sizes of images to be photographed by the large and small view cameras. The reflected light transmitting means includes a half mirror of a triangular prism, which enables a half of the light reflected by the inspecting part to transmit to a proceeding direction and the other half of the light to further reflect to an angle of 90 degree. A large view total reflection mirror of a planar mirror to reflect the light reflected by the half mirror at the angle of 90 degrees to identically proceed to the axis of the large view camera [the latter half of the light reflected by the half mirror at the angle of 90 degrees] and the large view lens. A first total reflection mirror including a small view of the triangular prism to change a proceeding direction of the light transmitted through the half mirror at the angle of 90 degrees; and a second total reflection mirror including a small view to reflect again the light of which proceeding direction was changed at 90 degrees by the first total reflection mirror, and to identically advance the light to the axis of the small view camera and the small view lens. Large and small view lenses drawing the light reflected by the total reflection mirror having the large view and the second total reflection mirror having the small view into the large and small view cameras.